Cavity Model Analysis of a Dual-Probe-Feed Circular Microstrip Patch Antenna

The cavity model is extended to analyze a dualprobe-feed circular microstrip patch antenna for both differential and single-ended operations. Particular emphasis is given to the impedance characteristics in order to understand the relationship between the differential and single-ended input impedances. It is shown that the differential input resistance is four times of the single-ended input resistance at the resonant frequency of the fundamental mode.